Maybe you went on vacation and brought back picture postcards. Maybe you stayed home and a few people sent you picture postcards. Or maybe you just have a collection of them, like I do, that are overflowing their boxes. If you don’t mind trimming and creasing them a bit, four of them can be used to make a cross flexagon.
You can always add to the narrative and write your own notes, poetry, or prose on the backs or alter the fronts with gesso or collaged imagery.